Photographic material



June 30, 1942. J. p. KENDALL ETAL 2,237,807

' v PnoToeaAraIc MATERIAL Filed March 5, 1541 (Light-sensitive layer Transparent 4 support mmm\fixxmxa\x\\\mkxm 1 3 fintihalation materialdispersed. in resin acids of tall oil INVENTORS John David KendallKenneth .lnhn Challis ATTORNEY v Patented June so, 1 942 PHOTOGRAPHIOMATERIAL John David Kendall and Kenneth John Challis,

Ilfo'rd, England, assignors to llford Limited,-- Ilford, England, aBritish company Application March 5, 1941, Serial No. 381,924

" In Great Britain April 12, 1 940 5 Claims. (Cl. 95- -8) This inventionrelates to anti-halation layers for light-sensitive photographicelements and has particular reference to light-sensitive photographicmaterials which consist of a support, a light-sensitive layer on oneside of the support and an anti-halation layer on the other side of thesupport. .V e

The production of a satisfactory a'nti-halation layer on light-sensitivephotographic material is a problem of some difiiculty. A satisfactoryantihalation layer should adhere well to the support and should have nodeleterious effect on the light sensitive layer, for example, when in'contact therewith as in the case offthe adjacent coils of film in aspool of film. Moreover, it is very important that the layer should bereadily removed or decolourised during the processing. of the lightsensitive material; nevertheless it should preferably not be watersoluble or it may'mark or become tacky on touching with moist fingers,or dye present in the layer may stain the fingers when thephotographicelement is handled.

It has now been found that the mixed resinacids derived from tall oilform a combination which is of particular value as the carrier for ananti-halation dye or pigment. According to the present invention,therefore, there are provided photographic elements comprising atransparent support, a coating of light sensitive material on one'faceof the support, and an anti-hala tion layer on the other face of thesupport which comprises a continuous film formed from the mixed resinacids of tall oil and an anti-halation dye or pigmentdispersedthroughout said film.

The mixed resin acids obtained from tall oil readily form a continuousfilm when dissolved in a suitable solvent; cast as a layer and dried,and.

such layers do not deleteriously affect silverhalide emulsion layerswhen brought into surface contact with them. Moreover, such layersadhere The mixed resin acids, from tall oilmay be obtained commerciallyas "Silvestic acid but the commercial material is preferably purifiedbefore use, e. g. by dissolving thematerial in a 10% solu,

tion, of sodium carbonate, filtering and reprecipitating the resin acidsby the addition of an It is a further advantage.

acid (for example, hydrochloric acid) to the filtrate.

The anti-halation dye or pigment selected for any particular case mustbe one which is absorptive of light of wavelengths'to which thephotographic emulsion is sensitive. The invention may be applied forexample to light sensitive film elements coated with panchromaticemulsions in which case a green or black dye is suitable, and

to orthochromatic and non-colour-sensitised emulsions in which cases redand yellow dyes are However, it is preferable to employ organicdyeinvention:

stuffs and particuluarlydyes which bleach out in the usual alkalinephotographic developing solutions, e. g. dye of the triphenyl methaneclass such as Benzaurin (Schultz, Farbstoff-Tabellen No. 887), AcidGreen G (Colour Index No. 666) Acid Magenta (Colour Index No. 692) andLissamine Green S. F. (Colour Index No. 670 of Supplement) Mixtures ofdyes or of pigments may be employed if desired.

, In the production of the anti-hala'tion layer of this invention aconvenient method is to form a .soliition'of the mixed resin acids in asuitable solvent, e. g. acetone or ethyl alcohol, and add to thissuflicient of the anti-halation dye or pigment to give the desiredtinctorial strength, then to coat the resulting solution as a layer onthe support layer of the photographic element, and thento dry the layerby evaporation of the solvent.

In the accompanying drawing a transparent throughan antihalationmaterial e. g. an antihalation dye or pigment.

The following specific examples illustrate the EXAMPLE 1 An ti-ha'lation layer for a photographic element carrying an ortho chromaticemulsion a litre of acetone. Solution"takes place in the cold. Thesolution is-filtered and then coated and dried as alayer on one face ofa glass plate which. carries on the opposite iace an orthochromaticsilver halide'emulsion. The anti-halation layer thus formed is firmlyadherent-to the glass and is readily dissolved away in alkalinedeveloper solutions.

EXAMPLE 2 Anti-halation layer for a photographic element carrying apanchromatic silver halide emulsion 200 grams of the mixed resin acidsfrom tall oil and 50 grams of Acid Green G are dissolved in one litre ofmethlyated spirit ('74 O. P.). Solution takes place in the cold. Afterfiltering the solution is coated and dried as an antihalation layer onone face of a glass plate which carries a panchromatic emulsion. on theopposite face.

Instead of Acid Green G the same weight of Lissamine Green S. F. may beemployed.

EXAMPLE 3 Anti-halation layer for a photographic element carrying apanchromatic silver halide emulsion In this example an antihalationlayer of somewhat deeper colour (i. e. of increased saturation) isproduced, the solvent mixture being modified to take up the largerquantity of dyestuff.

200 grams of the mixed resin acids from tall oil is dissolved in amixture of 800 ccs. of methylated spirit (74 O. P.) and 200 cos. ofethylene glycol monomethyl ether. To the resulting solution is added 100gms. of Acid Green G and the solution is shaken to facilitate solution.After filtering, the solution is coated and dried to form anantihalation layer as in Example 2.

EXAMPLE 4 Anti-halation layer for a photographic element carrying anorthochromatic silver halide emulsion 400 grams of the mixed resin acidsfrom tall said antihalation layer comprising a continuous film of themixed resin acids of tall oil and, dispersed throughout said film, acolouring matter which is absorptive of light of. wavelengths to whichthe light-sensitive coating is sensitive.

2. A photographic element comprising a transparent support, a coating oflight-sensitive material on one face of the support and an antihalationlayer on the other face of the support, said antihalation layercomprising a continuous film of the'mixed resin acids of tall oil and,dispersed throughout said film, a dye which is absorptive of lightwavelengths'to which the light-sensitive coating is sensitive, and whichis destroyed by alkaline photographic developer solutions.

3. A photographic element comprising a transparent support, a coating oflight-sensitive material on one face of the support and an antihalationlayer on the other face of the support, said antihalation layercomprising a continuous film of the mixed resin acids of tall oil and,dispersed throughout said film, a dyestuif of the triphenyl methaneclass which is absorptive of light of wavelengths to which the lightsensitive coating is sensitive. and which is destroyed by alkalinephotographic developer solutions.

4. A photographic element, comprising a glass support, a coating oflight-sensitive material on one face of the support and an antihalationlayer on the other face of the support, said antihalation layercomprising a continuous film of the mixed resin acids of tall oil and,dispersed throughout said film, a dyestuif of the triphenyl methaneclass which is absorptive of light of wavelengths to which the lightsensitive coating is sensitive and which is destroyed by alkalinephotographic developer solutions.

5. A photographic element comprising a transparent support, a lightsensitive silver-halide emulsion layer on one face of the support and anantihalation layer on the other face of the support, said antihalationlayer being composed of the mixed resin acids of tall oil havingdispersed therethrough a dye which is absorptive of wave lengths towhich the light sensitive layer is sensitive and which is destroyed byalkaline photographic developer solutions.

JOHN DAVID KENDALL. KENNETH JOHN CHALLIS.

